Chicago’s re-energized Board of Ethics is drawing the foul line again on baseball freebies — five months after forcing the Cubs to yank a lucrative offer to let aldermen purchase World Series tickets at face value.

In a memo sent this week, Ethics Board Chairman William Conlon is warning aldermen, department heads, the city clerk and treasurer that they are prohibited from accepting the White Sox offer to attend the team’s April 3 home opener against the Detroit Tigers and a pre-game “cocktail reception.”

“Because the value of this package is worth more than $50 to any single recipient and does not fall into any of the exceptions provide in the law, [such as personal appearance in connection with one’s official city responsibilities], it is prohibited under the gift restrictions” of the ethics ordinance, Conlon wrote.

“We have already advised the White Sox organization that the offer is prohibited and are by this memorandum, advising you as well,” he said. “. . . We advise those of you who may have already accepted to immediately return the tickets and decline the team’s offer.”

Howard Pizer, senior executive vice-president of the Sox, accepted Conlon’s ruling as the final word on an opening day freebie that has been a Sox tradition for decades.

“It’s irrelevant whether I agree or disagree with it. That’s their position and they make the rules. People abide by the rules,” Pizer said Tuesday.

Pizer was asked why the Sox extended the offer that includes free tickets, a cocktail reception and hors d’oeurves even after the very public flap over Cubs playoff tickets.

“We’ve done it this year as we’ve done it in prior years and never thought it would be an issue. . . . It’s been our tradition to do it. It seems like an appropriate thing to do for Opening Day,” he said.

Aldermen were told not accept a playoff ticket offer from the Chicago Cubs, and the Ethics Board has reminded them — and other city officials — that a ticket offer form the White Sox is similarly off-limits. | Sun-Times file photo

Southwest Side Ald. Matt O’Shea (19th), who advised his colleagues last fall to “buy your own damned tickets” said he’s following his own advice. He’s taking his son to the Sox home opener with tickets he purchased himself.

O’Shea applauded the Ethics Board for drawing a line that aldermen cannot cross.

“It sends a strong message that it’s a level playing field. It’s not special rules, special perks for us. Now, more than ever, Chicagoans need to know that it’s not the good ol’ days,” O’Shea said.

“There’s such a level of distrust and such a level of frustration with government at all levels. We have reached a critical point here on funding at CPS,” he said. “We have issues with the city and the state. There isn’t a sweetheart perk for the school teacher, the plumber or the policeman. There shouldn’t be one for aldermen.”

Ald. Brian Hopkins (2nd) agreed with the Ethics Board’s strong stand, even though he was among the aldermen openly complaining about the ruling that applied to Cubs’ playoff tickets.

“When you package those things together, they made a determination that it’s in excess of $50. You really can’t dispute that,” he said.

Fans have their tickets scanned before Game Three of the 2016 World Series between the Chicago Cubs and the Cleveland Indians at Wrigley Field

Fluctuating prices in the secondary ticket market were frustrating to one alderman, who said it created uncertainty in applying ethics rules on the value of gift that could be accepted. | Getty Images

Hopkins noted that his complaint about the Cubs’ ruling stemmed from what he called the “difficulty of using secondary market value” to determine whether the $50 gift limit has been violated.

“They’re worth $100 one day, $200 the next day and $40 on the third day, which is what happens on StubHub. You can’t do that,” Hopkins said. “If it’s gonna be an ethical violation because the secondary market says the ticket was worth more than $50, when? What day? What time of the day?”

Last fall, aldermen vented their anger about the Ethics Board ruling that forced the Cubs to yank a lucrative offer to let aldermen buy World Series tickets at face value.

Ald. Milly Santiago (31st) argued then that she was just a “poor alderman” who couldn’t afford to pay thousands of dollars to purchase World Series tickets on the secondary market.

She branded the controversy triggered by the Ethics Board’s narrow interpretation of the city’s gift ban “kind of insulting, humiliating and embarrassing for us” for a perk that wasn’t all that hot.

A few days later, Santiago, whose annual salary is $116,208, apologized saying she “never intended to offend anybody.”

On Tuesday, O’Shea predicted that aldermen similarly disgusted with the Ethics Board’s ruling would hold their fire.

“I’ve got to believe that, if they’re upset about it, they’ll keep their opinion to themselves because you know what happened last time when a couple of them spouted off,” O’Shea said.

The White Sox and the Guaranteed Rate mortgage company announced a 13-year naming-rights deal last year. | Charles Rex Arbogast/Associated Press